.titulo {
    margin-top:-20px;
    background-color: #428BCA;
    color: white;
}
footer {
    display: inline-block;
    position: relative;
    background-color: #222222;
    color: whitesmoke;
    width: 100%;
    padding-top: 5px;
}
body { 
    padding-top: 70px;
}
.alerta {
    position: fixed;
    bottom: 5%;
    left:20%;
    right:20%;
    text-align: center;
    display: none;
}
@media screen and (min-width: 992px) {
    .login {
        margin-top: 100px;
        margin-left:150px;
        margin-right:150px;
        padding-top: 20px;
        padding-left: 50px;
        padding-right: 50px;
        border-style: solid;
        border-width: 1px;
        border-color: whitesmoke;
        box-shadow: 0px 0px 3px 3px whitesmoke;
    }
}
@media screen and (min-width: 768px) and (max-width: 992px) {
    .login {
        margin-top: 80px;
        margin-left:120px;
        margin-right:120px;
        margin-bottom: 40px;
        padding-top: 15px;
        padding-left: 25px;
        padding-right: 25px;
        border-style: solid;
        border-width: 1px;
        border-color: whitesmoke;
        box-shadow: 0px 0px 3px 3px whitesmoke;
    }
}

@media screen and (max-width: 768px) {
    .login {
        margin-top: 50px;
        margin-left:50px;
        margin-right:50px;
        margin-bottom: 25px;
        padding-top: 10px;
        padding-left: 15px;
        padding-right: 15px;
        padding-bottom: 10px;
        border-style: solid;
        border-width: 1px;
        border-color: whitesmoke;
        box-shadow: 0px 0px 3px 3px whitesmoke;
    }
}